• Atmosphere
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• v.33 no.1
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• pp.1-20
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• 2023

Holding the longest observation data from April 1904, Busan is one of the essential points to understand the climate variability of the Korean Peninsula without missing data since implementing the modern weather observation of the South Korea. Busan is featured by coastal areas and affected by various climate factors and fluctuations. This study aims to investigate climate variability and changes in climatic variables, extremes, and several weather indexes. The statistically significant change points in daily mean rainfall intensity and temperature were found in 1964 and 1965. Based on the change point detection, 117 years were divided into two periods for daily mean rainfall intensity and temperature, respectively. In the long-term temperature analysis of Busan, the increasing trend of the daily maximum temperature during the period of 1965~2021 was larger than the daily mean temperature and the daily minimum temperature. Applying Ensemble Empirical Mode Decomposition, daily maximum temperature is largely affected by the decadal variability compared to the daily mean and minimum temperature. In addition, the trend of daily precipitation intensity from 1964~2021 shows a value of about 0.50 mm day^-1, suggesting that the rainfall intensity has increased compared to the preceding period. The results in extremes analysis demonstrate that return values of both extreme temperatures and precipitation show higher values in the latter than in the former period, indicating that the intensity of the current extreme phenomenon increases. For Wet-Bulb Globe Temperature (effective humidity), increasing (decreasing) trend is significant in Busan with the second (third)-largest change among four stations.

• Journal of Service Research and Studies
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• v.13 no.1
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• pp.1-26
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• 2023

We analyze the effects and related factors of Smart Factory adoption. 110 and 325 samples were collected by median-size-industry matching method, respectively, of adopting and non-adopting companies. We use financial statement data (ROA, etc.) from the year before adoption to the fourth year after adoption. Abnormal operating performance and annual abnormal changes are obtained according to event study method, and analyzed by Wilcoxon signed-rank test and t-test. ROA and sales growth rate demonstrate short-term effects after adoption, but not long-term effects. As a result of regression analysis to examine if the three factors of labor intensity, R&D intensity, and prior financial performance have moderating effect, the moderating effect of R&D intensity and prior financial performance is confirmed. In addition, we perform regression analysis to confirm performance effects of early and late adoptions and whether prior financial performance and organization size have moderating effect. It is confirmed that the later the time of adoption, the greater the effect of adoption in the long term and the moderating effect of prior financial performance and organization size is confirmed.

• Structural Engineering and Mechanics
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• v.81 no.2
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• pp.219-230
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• 2022

Due to the large number of railway bridges along China's high-speed railway (HSR) lines, which cover a wide area with many lines crossing the seismic zone, the possibility of a HSR train running over a bridge when an earthquake occurs is relatively high. Since the safety performance of the train will be threatened, it is necessary to study the safety of trains running over HSR bridges during earthquakes. However, ground motion (GM) is highly random and selecting the appropriate ground-motion intensity measures (IMs) for train running safety analysis is not trivial. To deal this problem, a model of a coupled train-bridge system under seismic excitation was established and 104 GM samples were selected to evaluate the correlation between 16 different IMs and train running safety over HSR bridges during earthquakes. The results show that spectral velocity (SvT₁) and displacement (SdT₁) at the fundamental period of the structure have good correlation with train running safety for medium-and long-period HSR bridges, and velocity spectrum intensity (VSI) and Housner intensity (HI) have good correlation for a wide range of structural periods. Overall, VSI and HI are the optimal IMs for safety analysis of trains running over HSR bridges during earthquakes. Finally, based on VSI and HI, the IM thresholds of an HSR bridge at different speed were analyzed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.1
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• pp.21-26
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• 2013

In recent study, infiltration analysis considering rainfall intensity is more economical and practical than existing analysis method. Revised construction slope design standard is also stated to full-fill infiltration analysis considering rainfall for practical stability review. Infiltration analysis considering rainfall for practical stability review. But, to infiltration analysis, the process is complicated by ground impermeability and rainfall intensity. In this study, we perform infiltration analysis to charge infiltration conditions, soil type and rainfall characteristics, for more pratical stability review. Using the result, we can suggest construable condition on the assumption that soil is saturated up to surface zone.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.4
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• pp.306-313
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• 2011

The damage tolerance analysis is required to guarantee the structural safety and the reliability for aircraft components. The damage tolerance method, which evaluate the life considering the initial crack, considers a fatigue design model of the aircraft main structure. The fatigue crack growth life should be calculated in damage tolerance analysis and the inspection time to define the replacement cycle. In this paper, the damage tolerance analysis is performed for a turbine wheel which has complex geometry. The equation of the stress intensity factor for complex geometry is hard to know, so that they are usually processed by finite element analysis which takes long time. To solve this problem, the stress intensity factors at specified crack are obtained by the FEA and the crack growth life is evaluated using the surrogate model which is generated by the regression analysis of the FEA data. From the results, the efficiency of the crack growth life calculation and the damage tolerance analysis could be increased by taking the surrogate model.

• Journal of the Korean Society of Physical Medicine
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• v.8 no.4
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• pp.539-547
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• 2013

PURPOSE: This study examined the effects of exercise of diverse intensities on the expression of TNF-${\alpha}$(tumor necrosis factor-${\alpha}$) in the spinal cord in osteoarthritic rats. METHODS: Over a period of four weeks, the authors applied treadmill exercise programs of diverse intensities to Sprague-Dawley rats, to which intra-articular injection of monosodium iodoacetate(MIA, $3mg/50{\mu}l$, diluted in saline) was applied to the right knee joint to induce osteoarthritis. The four-week exercise program was not carried out with the control group(CG, n=10). Exercise programs of applicable intensities were applied to the low-intensity exercise group(LEG, n=10), moderate-intensity exercise group (MEG, n=10), and high-intensity exercise group(HEG, n=10) over the four weeks. Observations were made of expression of TNF-${\alpha}$ in the spinal cord in osteoarthritic rats using western blot analysis. RESULT: there were significant differences(p<.05) in the comparison of expression of TNF-${\alpha}$ between the four groups involved. The expression of TNF-${\alpha}$ in the spinal cord, the LEG and HEG had more elevated expression significantly than the CG(p<.05). But the MEG had reduced expression significantly than the CG(p<.05). CONCLUSION: These study results suggest that moderate-intensity exercise is effective in inhibition TNF-${\alpha}$ in the spinal cord. They also indicate that in prescribing exercise to treat osteoarthritic patients, exercise of moderate intensity is most suitable to patients' chronic pain, rather than low or high intensity.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.643-646
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• 2006

An operational calibration is applied to improve radar rainfall intensity using rainfall obtained from rain gauge. The method is applied under the assumption of the temporal continuity of rainfall, the rainfall intensity from rain gauge is linearly related to that from radar. The method is applied to the cases of typhoon and rain band using the reflectivity of CAPPI at 1.5km obtained from Jindo radar. The CAPPI is obtained by bilinear interpolation. For the two cases, the rainfall intensities obtained by operational calibration are very consistent with the ones by the rain gauges. The present study shows that the correlation between the rainfall intensity by operational calibration and rain gauges is better than the one between the rainfall intensity by M-P relationship and rain gauges. The correlation coefficients between the total rainfall intensity obtained by operational calibration and rain gauges in typhoon and rain band cases are 0.99 and 0.97, respectively. Areal rainfalls are estimated using the field of calibration factor interpolated by Barnes objective analysis. The method applied here shows an improvement in the areal rainfall estimation. For the cases of typhoon and rain band, the correlation between the areal rainfall by operational calibration and rain gauges is better than the one between the area rainfall by M-P relationship and rain gauges. The correlation coefficients between the areal rainfall obtained by operational calibration and rain gauges in typhoon and rain band cases are 0.97 and 0.84, respectively. The present study suggests that the operational calibration is very useful for the real-time estimation of rainfall intensity and areal rainfall.

• Journal of Korean Biological Nursing Science
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• v.22 no.2
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• pp.139-147
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• 2020

Purpose: The purpose of this study was to determine the effects of different intensity of aerobic exercise for four weeks on cardiovascular risk factors, reactive oxygen, and antioxidant enzymes in old mice. Methods: Eighteen male C57BL/6 mice age 18 months were randomly classified into the control group (n= 6), the moderate intensity exercise group (n= 6), and the low intensity exercise group (n= 6). The training groups performed the aerobic exercise twice daily for 20 minutes, five days weekly for four weeks. Data were analyzed using descriptive statistics, analysis of variance (ANOVA), the Chi-square test, and the Tukey's test with the SPSSWIN 21.0 program. Results: In this study, among the risk factors of cardiovascular disease, blood sugar (BS) (p= .023) and total cholesterol (TC) (p= .001) were significantly different between the moderate intensity exercise group and the control group. Additionally, there were significant differences in the reactive oxygen malondialdehyde (MDA) (p= .001), the antioxidant enzymes superoxide dismutase (SOD) (p< .001) and glutathione reductase (GR) (p= .015) between the moderate intensity exercise group and the control group. Conclusion: This finding suggests that moderate intensity aerobic exercise promotes the activity of antioxidant enzymes and lowers cardiovascular risk factors in older mice.

• Atmosphere
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• v.29 no.4
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• pp.381-390
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• 2019

This study investigates the impacts of urban land-use fraction and temperature advection on the urban heat island intensity over the Seoul metropolitan area using the UM (Unified Model) with the MORUSES (Met Office Reading Urban Surface Exchange Scheme) during the heat wave over the region from 2 to 8, August 2016. Two simulations are performed with two different land-use type, the urban (urban simulation) and the urban surfaces replaced with grass (rural simulation), in order to calculate the urban heat island intensity defined as the 1.5-m temperature difference between the urban and the rural simulations. The land-use type for the urban simulation is obtained from Korea Ministry of Environment (2007) land-use data after it is converted into the types used in the UM. It is found that the urban heat island intensity over high urban-fraction regions in the metropolitan area is as large as 1℃ in daytime and 3.2℃ in nighttime, i.e., the effects of urban heat island is much larger for night than day. It is also found that the magnitude of urban heat island intensity increases linearly with urban land-use fraction. Spatially, the estimated the urban heat island intensities are systematically larger in the downwind regions of the metropolitan area than in the upwind area due to the effects of temperature advection. Results of this study indicate that urban surface fraction in the city area and temperature advection play a key role in determining the spatial distribution and magnitude of urban heat island intensity.

• The Journal of the Korea Contents Association
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• v.18 no.10
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• pp.158-164
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• 2018

The purpose of this study is to statistically analyze the signal intensity pattern according distance from the surface coil center and to maintain optimal signal intensity under clinical circumstances where the surface coil centers are not correctly positioned due to various causes. The cylindrical fluid phantom was placed and moved from the coil center in vertical direction with 1 cm increments. The signal intensities were measured and compared. As a result, the signal intensity showed no significant difference within 4 cm and 1 cm from in T1 weighted images while in T2 weighted images the signal intensity was maintained up to 5 cm and lower 3 cm in the upper and lower direction from the coil center. In conclusion, to maintain the optimal signal intensity the target region should be located within the reference distances proposed in this study.